John has mentioned in here that he never draws banks he is cinching, unless it is required to get out of a kiss, or perhaps for safety or position play.
I'm with you though. I use draw sometimes and dont know why. i do this less now though, and with good results. I have come to the conclusion that bank pool is essentially about shortening banks up, and using a lot of center ball, with touches of english (both inside and outside come up a lot). I used to use too much spin, now I have toned that down and i'm more accurate.... I see those "shortened" angles, and go from there.